The invention relates to tubular section members intended in particular for use as fluid flow ducts, or as admission or exhaust silencers in the car industry field, in building, or in the machines and engine industry, for example.
When it is necessary to attenuate transmission of sound in fluids flowing along tubes, it is general practice to use sound absorbing materials which are disposed inside the tubes and/or inside resonators tuned to the frequencies or frequency bands to be attenuated and which are connected in series or in parallel with the fluid flow tubes. Implementing such known means so that they are genuinely effective, turns out in general to be difficult and expensive.
In general, it is already known to form reinforced-wall tubes or pipes, by spiral-winding an extruded tubular section member, the turns touching one another and being bonded together (see for example U.S. Pat. No. 5,060,698 and EPO 0 418 760). It is also known, e.g. from patent DE 3 930 528, to form a pipe having a reinforced wall by spiral-winding an extruded tube, and then spiral-winding reinforcement between the turns of the tube. However, that known technique serves only to manufacture reinforced-wall tubes which are generally of large diameter, and which cannot serve as silencers.
A particular object of the invention is to provide a solution to these problems that is simple, effective, and cheap.